Electric magnetic thermostat for type melting machines



ELECTRIC MAGNETIC THERMOSTAT FOR TYPE MELTING MACHINES 2 SHEETS-SI-IEET 1 Filed Nov. 12. 1948 d a m ,m 6 N w y m m I m a a w 9 A H E M M I w w 5 M w 3 O i M o z m. w. 5 .w z W ..M m. ".3 W F m 6 "a 57 5 wwm a x fl 9 -LIIII L T l lllilii ill m Patented Mar. 3, i953 ELECTRIC MAGNETIC THERMOSTAT FOR TYPE MELTING MACHINES Enrique Villarreal, Mexico City, Mexico Application November 12, 1948, Serial No. 59,438

4 Claims.

This invention relates to combination electromagnetic and thermostatic control devices for melting pots of type setting machines or for machines or devices for other purposes, and in particular the invention relates to an automatic switch actuated by an expansion bar, which also actuates a pointer, wherein expansion of the bar opens the switch and as the bar cools, the switch is closed completing a circuit through solenoids that close contacts in a main circuit to electric heating elements of the melting pot.

The purpose of this invention is to provide means for maintaining comparatively constant temperature in metal melting pots and in which the control means may readily be adjusted to vary the temperature of the metal.

This application is a continuation, in part, of my co-pending application, filed February 15, 1946, with Serial Number 647,895, and now abandoned for Electro-Magnetic Thermostat for Type Melting Machines.

Various devices, and particularly thermostatic devices of diiferent types have been provided for controlling the temperature of the molten metal in melting pots and while these devices operate eventually, it takes considerable time for the thermostat to cool sufliciently to permit contact to complete the circuit after the circuit has been opened. With this thought in mind, this invention contemplates a control device having electro-magnetic actuating means in combination therewith wherein the controls actuate to instantly close the circuit to the electric heating elements of the melting pot when the temperature of metal in the melting pots comes to a predetermined degree.

The object of this invention is, therefore, to provide an automatic control device for maintaining constant temperature in melting pots particularly in type setting machines wherein as the material in the melting pot reaches a predetermined degree, a circuit is broken through a solenoid that opens a switch in the circuit to the melting pot so that the heat is instantly turned off and all circuits are broken until the temperature of the material in the melting pot drops to a predetermined degree.

Another object of the invention is to provide a control device for heating elements of metal melting pots in which visible means is provided for indicating the temperature of the metal in the melting pot.

Another object of the invention is to provide a combination thermostatic and electro-magnetic control for heating elements of metal melt- 2 ing pots in which the electro-magnetic device actuate instantly to break the circuit as the temperature of the metal in the melting pot reaches a predetermined degree and also actuates instantly to again apply the heat when the temperature drops to a predetermined degree.

A further object of the invention is to provide in combination an electro-magnetic and thermostatically controlled switch for maintaining constant temperatures in metal melting pots which is of a comparatively simple and economical construction.

With these and other objects and advantages in view, the invention consists of the new and useful combination, construction and arrangement of parts as hereinafter more fully described, set forth in the claims appended hereto, and disclosed in the accompanying drawings forming part hereof, wherein:

Figure 1 is a view showing a front elevation of the switch with the cover removed and with part of the expansion bar broken away;

Figure 2 is a view showing a side elevation of the switch with the housing removed and with. part of the expansion bar broken away;

Figure 3 is a vertical cross-section through the switch taken substantially on line 3-3 of Figure 5;

Figure 4 is a sectional view through the switch taken on line 44 of Figure 3;

Figure 5 is a plan view of the switch showing the parts in elevation, and;

Figure 6 is a wiring diagram illustrating the circuit of the device.

Referring now to the drawings wherein like reference characters denote corresponding parts, the control switch of this invention includes a thermo-responsive or tubular expansion bar It carried by a rod l I from a base [2 and the expansion of the bar It! opens contacts I3 and hi through an arm l5 and as the contacts open a circuit to solenoids l6 and i1 is broken so that an arm [8 is released which raises a contact bar l9 that opens a circuit to the heating element 28 of a melting pot.

The element 10 is secured on the bar H by a nut 21 and the bar H is rigidly mounted in an inverted U-shaped bracket 22 by nuts 23 and 24 and a lock nut 25. The bracket 22 is secured to the base l2 by screws 26 and the upper end of the element [0 i provided with a ring 2'! that engages the trigger 28 that is pivotally mounted in upwardly extended ears 29 and 30 of the ring 27 by a pin 3|.

.The'ring 21. alsoengages an end 32 of a lever 33 which is pivotally mounted on the base I2 by a pin 34 in a clip 35 on a bar 36. The bar 36 is secured to the base I2 by a screw 31. The opposite end of the lever 33 engages an extension 38 of a pointer 39 which is pivotally mounted on the bar 39 by a pin 49 in a clip M and the upper end of the pointer is in registering engagement with the graduated scale 42 which is provided With numerals 43 to indicate the rise in temperature in the melting pot. A spring 44 is provided on the bar 36 and positioned with the outer end under the extended end 38 of the pointer whereby the pointer is maintained in the position illustrated in Figures 1 and 4 when metal in the melting pot is cool.

The arm I is provided with a. bifurcated lower end in which a bar 45 is secured by bolts 46 and the lower end of the bar 45 is secured to a. horizontally disposed bar 4'! by a screw 48. The bar 41 and the arm I5 to which the bar 41 is attached through the bar 4-5 are carried by spring elements 49 and 5.9 which are mounted on the outer face of the bracket 22 by screws 94 and 52. The bar 41 is provided with an adjusting screw 53, the lower end of which extends downward to engage the upper surface of the trigger 29.

On the upper part of the arm I9 is a. laterally disposed arm 54 that carries a contact 55 on which the point I4 is positioned and as the element I9 expands it moves the trigger -28 upward which, in turn, through the adjusting screw '53, actuates the arm I5 about the spring elements 59 and 59 and moves the contact I4 laterally away from the contact I3 thereby breaking a circuit to the solenoids I6 and H, The arm It being suspended by the spring elements 49 and 59 is suspended with a swinging action and upward movement caused by pressure on the lower end of the screw 53 swings the lower end of the arm outwardly .and the upper end inwardly whereby the contact I4 moves'laterallyawayfmm the contact I3 and the inner end of the screw 56 engages the spring 51. The arm I5 is formed ofinsulatingmaterial and .the upper end is provided with an adjusting screw 59 \vhichengages a Sp 1 5 thatextends downward from a frictionally mounted :pin59 that is positioned in an opening 59 in a support 69 on an upper base member '6! that is supported above the base l2 by posts 62 and 63. With the parts arranged in thismanner, the position of the arm I5 may be adjusted so that the points I3 and I4 moving normal to their contact faces separate exactly when the temperature of metal in the melting pot reaches a predetermined degree.

The opposite terminals of the solenoids IEand I! are connectedbya Z-shaped bar 64 as shown in Figure 1, and the arm I8 is pivotally mounted by a pin 95 in a bracket 96 on the bar 64. The arm I8 is positioned over an arcuate flat spring steel arm 67, asshown in'Figure 3, and the contact bar I9 is mounted on the outer end of the arm 67 through a plate 68, the plate being at.- tached to the arm 97 by ,a rivet 69 and to the bar I9 with a screw I9. The armfil isattached to a channel shapedjolip II by a rivet i2 and the clip I! is pivotally mounted in the recess in the outerend of the support 69 by a pin 13. The arm 51 is resiliently urged wherein the outer end, carrying zthegbar I9 is held upwardly when the armis released-{by aspring '14 on the pin 13, one end of thespring 14 being held in a recessI5 in the support ,59 and the other end 16 being positioned under the clip II. Upward movement ofthe arm 61: is crestrained :by; a' projection 7:] on

.4 the spring 51 and the position of the arm 6'! is also governed by an adjusting screw 18 in the support 69. When the solenoids are de-energized, the bar I9 is held in contact with the contacts 89 and BI by the. projection 11 on the spring 51 and the circuit is, therefore, held closed until the expansion of the outer tube I9 actuates the arm I5 to open the contacts I3 and I4 whereby the inner end of the screw 56 moves the spring 51 over until th projection releases the arm 61 wherein the arm I8 is raised by the action of the spring in the lower part of the arm 61 so that it is separated from the core I9 of the solenoid I! and in this position, the contact bar I9 is separated from the contacts 89 and 8| which are suspended by spring clips. 82 and 83 from blocks 84 and 89 on the upper insulated base 6|. The blocks and clips are held by bolts 86 and 91 respectively and contact bars 88 and 89 extend from the upper ends of the posts formed by the bolts 99 and 8?, respectively.

The arm IS, the upper base 6i and also. the bars 59 are formed of insulating material.

The support 69 is mounted on the upper base GI and is secured thereto by albolt99. The contact point I 3 is also carried by the upper lbase 9i being mounted thereon through arms 9| and 92 which are connected by .a screw 93 .andthe upper end of the arm 92 is connected with the upper base .6! by a. bolt v94. A set screw 95 is provided in the support 9 to 'lock the spring 57 in the adjusted position through the member58. The spring 5? extends through an opening 99 inthe arm Bl, as shown in Figure 3. A plate!" may be secured to the posts 62 and 63 by screws 98 and an upper plate 99 on which the graduated scale 42 is positioned is attached to the upper insulating base Si by screws I99 through clips I91.

As illustrated in the wiring diagram, shown in Figure 6, current is applied to the device through wires I92 and I93 with the wire I92 provided with a main switch I94 and connected to a heating element of the metal melting pot by a wire I95. .Trom'the heating element, which is indicated by the numeral 29, the current is connected to the contactBI byawi-re I96. The contact 9| is connected 'to the contact 89 by a bar I9 and the contact 89 is connected to the wire I93 by wires I97 and MB-with a fuse I99 connecting the wires. The contact point 13 on the arm I5 is connected to thecontact 8I by a wire H9 and the contact I4 is connected to the solenoid i? by a wire Hi. The solenoids are connected by the bar 94 and the opposite terminal of the solenoid I6 is connected to the wire 891 through wires I12 and H3 with afuse H4 in these wires.

The contact bar I9 is elevated when the device is not in use so that the'points 89 and 8| are separated and-when the main switchI 941s closed, av circuit is completed through the-solenoids passing from the wire I92 through the wiresIllS, I96, I I 9 and I I i to the solenoidsand .through the wires H2, H3, I9? and I99 backto the Wire I93. As soon as the solenoids are energized, thebar I9 is drawn downward by thebars I8 to close the contact points 89 and BI and-this circuit will remain closed until the temperature of metal in the melting pot reaches a predetermined degree wherein the expansion bar I9. will raise the arm L5 to break the circuit through the contactpoints I 3 and I 4. When the'temperature drops to .a predetermined degree, .the circuit :will be completed :through the points. I3. and I 4a-nd therebythroug-h the heating element. This cycle of continuously opening and completing circuits will be continued to maintain a standard constant temperature in the melting pot. The projection 11 on the spring 51 serves to hold the bar l9 selectively closed.

It will be understood that modifications may be made in the design. arrangement and other parts without departing from the spirit and scope of the invention.

What is claimed is:

l. A temperature control comprising a stationary contact, a movable contact positioned to engage the stationary contact, means for maintaining said movable contact in engagement with said stationary contact, a thermo-responsive element for actuating the movable contact to disengage the stationary contact as the thermoresponsive element expands, a main operating circuit and an auxiliary circuit, a switch connected in the said main operating circuit, a solenoid connected in the auxiliary circuit for h0ld ing the switch of the main operating circuit closed, and resilient means urging the switch of the main operating circuit open for opening the circuit when the solenoid is deenergized, said stationary and movable contact points connected in said auxiliary circuit whereby the circuit for the solenoid is broken upon expansion of the thermo-responsive element.

2. A temperature control comprising a stationary contact, a movable contact positioned to engage the stationary contact, means for maintaining said movable contact in engagement with said stationary contact, a, thermo-responsive element for actuating the movable contact to disengage the stationary contact as the thermo-responsive element expands, means adjusting the actuating means, a main operating circuit and an auxiliary circuit, a switch connected in the said main operating circuit, solenoid connected in the auxiliary circuit for holding the switch of the main operating circuit closed, and resilient means urging the switch of the main operating circuit open for opening the circuit when the solenoid is deenergized, said stationary and movable contact points connected in said auxiliary circuits whereby the circuit for the solenoid is broken upon expansion of the thermo-responsive element.

3. In a control for maintaining substantially constant temperature in fluids, the combination which comprises a base having an opening therethrough, an inverted U-shaped bracket mounted on the base and positioned over the opening therein, a depending stationary rod carried by the bracket and extended through the opening in the base, a tubular thermo-responsive element positioned on the rod for actuating said rod, a trigger positioned in the bracket and carried on the upper end of the thermo-responsive element,

a vertically disposed arm flexibly mounted on the bracket, a movable contact point carried by the arm, a stationary contact point carried by the base and positioned to engage the movable contact point, an electro-magnet carried by the base, a main operating circuit, an uxiliary circuit in which the electro-magnet is positioned, a switch having a bar and contact points positioned in the said main operating circuit, means resiliently suspending the switch bar above the contact points and spaced therefrom, a contact arm positioned to be influenced by the electromagnet to actuate the switch bar to close the main operating circuit, and means adjusting the position of the said switch bar suspending means.

4. In a control for maintaining substantially constant temperature in fluids, the combination which comprise a base having an opening therethrough, an inverted U-shaped bracket mounted on the base and positioned over the opening therein, a depending stationary rod carried by the bracket and extended through the opening in the base, a tubular thermo-responsive element positioned on the rod for actuating said rod, a trigger positioned in the bracket and carried on the upper end of the thermo-responsive element, a vertically disposed arm flexibly mounted on the bracket, a movable contact point carried by the arm, a, stationary contact point carried by the base and positioned to engage the movable contact point, an electro-magnet carried by the base, a main operating circuit, an auxiliary circuit in which the electro-magnet is positioned, a switch having a bar and contact points positioned in the said main operating circuit, means resiliently suspending the switch bar above the contact points and spaced therefrom, a contact arm positioned to be influenced by the electro-magnet to actuate the switch bar to close the main operating circuit, means adjusting the position of the said switch bar suspending means, an upper insulated base positioned above the base of the control, a support carried by the upper base on which the switch points and switch bar suspending means are mounted, and means mounting the electro-magnet on the upper base.

ENRIQUE VILLARREAL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,171,254 Ruckle Feb. 8, 1916 1,571,390 Apthorpe Feb. 2, 1926 2,133,888 Bloch Oct. 18, 1938 2,356,612 Pfafi Aug. 22, 1944 2,369,715 Classon Feb. 20, 1945 

